A 10-month-old male with glutaric aciduria type-1 (GA-1) is reported. This patient showed frequent partial motor seizures, irritability, and involuntary movements, including oral dyskinesia at the age of 3 months. On admission, magnetic resonance (MR) scanning revealed a chronic subdural hematoma and widening of the bilateral insular cisterns. Urine organic acid analysis showed marked excretion of glutaric acid, 3-hydroxy glutaric acid and glutaconic acid, suggesting GA-1. Removal of the subdural hematoma was effective for the irritability but not for the extrapyramidal signs. This is the first report of a subdural hematoma as an initial symptom in a patient with GA-1. However, the complication of subdural fluid collection in GA-1 is not rare. To our knowledge, of 29 patients with GA-1 who underwent computed tomographic or MR scans, 5 had subdural fluid collection. Disproportional hypoplasia of the temporal lobes may be a suggestive etiology of subdural fluid collection/chronic subdural hematoma.